Method of operating gas and oil furnaces.



A. M. HUNT & J. B. SPEED.

METHOD 01-" OPERATING GAS AND OIL FURNACES.

APPLICATION FILED MAILB, 1913.

1,1 14,767. Patented 00c. 27, 1914.

WITNESSES. INVENTgO/g} Z.

4 2%? w an A TTORNE Y THE NORRIS PETERS ca. PHOIOLHHO. WASHINGTON, r). l

UNITED s'rA'rEs PATENT OFFICE.

ANDREW MURRAY HUNT AND JAMES B'UcKNEE. SPEED, or BERKELEY, CALIFORNIA.

METHOD OF OPERATING GAS AND OIL FURNACES.

To all whom it may concern Be it known that we, A DREW MURRRAY HUNT and JAMES BUOKNER SPEED, citizens of the United States, residing at Berkeley, in the County of Alameda and State of California, have invented certain new and useful Improvements in Methods of Operating Gas and Oil Furnaces, of which the follow ing is a specification.

Our invention relates to the operation of furnaces which burn gas or oil, and while our said invention is applicable to any gas or oil fired furnace in which the charge or burden is directly subjected to the flame and heated gases, as, for example, a reverberatory furnace for smelting or for roasting or desulfurizing ores, it is especially adapted for kiln furnaces, such, for example, as are used in the manufacture of Portland cement. I

The object of our invention is to increase the heating capacity of gas or oil fired furnaces of this type, that is, those in which the charge or burden is directly subjected to the flame and heated gases, by causing the heated products of combustion to give up to the charge, by radiation, a greater proportion of heat than they ordinarily'yield.

To this end our invention consists essentially in introducing into the furnace to mingle with the heated gases of combustion a small amount of incombustible dust capable, as an artificial ash effect, of producing an incandescent ashafterglow. Considering first the use of gas or oil in a furnace for heating a steam-boiler, and the use of such fuel in a furnace, such as a kiln, for example, the plain distinction may be drawn that in the case of the steam boiler, the hot, though nonluminous gases resulting from combustion can give their heat to the relatively cold tubes of the boiler at locations remote from the flame combustion chamber, by reason of the hot gases rubbing over the tubes; while in the kiln, little or no heat is taken from the burnt gases after they cease to be luminous. In an oil or gas flame, the luminosity ceases as soon as the free carbon is consumed, the end of the flame being sharp and clean cut. Therefore, unless the flame fills practically the entire length of the kiln, comparatively little benefit is derived from a long kiln. This comparison thus indi cates the problem which gas and oil fired Specification of Letters Patent. P t t t 27, 1 4 Application filed March 8, 1913.

Serial No. 752,974.

furnaces of the kindor type to which our invention is directed, present for solution.

ash. After the combustion of the coal there is a long trail of incandescent ash-afterglow, which enables the hot gases to give up their heat by radiation. But in gaseous and liquid fuel there is no ash or solid residue, and there is therefore no ash-afterglow; and as has been stated, the burnt gases afterthey cease to be luminous, give up but little heat to the kiln charge. In accordance with our invention, this incandescent after-glowcan be produced in such a kiln or furnace by introducing into the furnace a very small amount of incombustible dust consisting of finely divided incom bustible material, which practically becomes. an artificial ash. I More specifically, in the case of a cement kiln, the incombustible dust thus introduced into the furnace may be any convenient dust, as, for example, raw mix, that is, a

mixture of limestone and clay before being burnt; or, it may be ground cement, or powdered limestone. A very small blast of this dust rendered extremely fine and blown in at the front of the kiln produces a brilliant glow throughout the kiln and permits the working of a shorter and larger flame extending only about of the length of the kiln. The effect of the after-glow is to heat the incoming charge mix by the gases which would otherwise be non-luminous, and hence unable to radiate their heat. The amount of dust thus blown in may be, in practice, about equal in amount to the dust due to the coal ash in coaldust-burning kilns. In a rotary cement kiln of 600 barrels per day capacity and 125 feet long, we may state that a good working amount of added dust is about 225 pounds per hour ground to a mean diameter of particle of 1/1000 of an inch or less. Any suitable amount may, however, be used.

The accompanying drawings illustrate an apparatus suitable for carrying out our method.

Figure 1 is a front elevation showing schematically a kiln room with the flame dusting pipe applied. Fig. 2 is a plan View enlarged and broken of the dust pipe and the chain-drag. Fig. 3 is a fragmentary view, enlarged, showing one kiln and its flame dusting appurtenances.

In Fig. 11 are the kilns; 2 is an air pipe; 3 is the dust pipe, passing in front of all the kilns; and at are the dust spouts.

In Fig. 25 is the dust bin, with which the dust pipe 3 communicates, 6 are guide sprockets for the chain-drag 7 in the pipe 3, and 8 is the driving sprocket for the chaindra l'ii Fig. 39 is a hood of one of the kilns 1. a is one of the dust spouts which cornmunicates at its upper end with the dust pipe 3, through a. small hole 10 in the bottom of said pipe. The spout is carried by a sleeve 11 fitted on the pipe and adapted to turn thereon. The lower end of the spout -2- has delivery end 12 which may be inserted in the hood 9 of the furnace front. 13 is the connection to the air pipe 2, and 1-1 is the air injector in the delivery end 12 of the dust spout. The dust from the bin 5 is carried along by the chain-drag 7, through the pipe 3. The dust drops down through the holes 10 into the spouts 1 and is blown by the injectors 14% into the kilns. To shut the dust off from any given spout, the latter need only be swung outward, as shown, in dotted lines, in Fig. 3, thereby closing the hole 10.

It will be understood that the introduction of the dust by blowing it in, as We have described, is illustrative of but one method of introduction. The dust may however be introduced in any manner found convenient or desirable.

We claim:

1. The method of applying heat to a burden or charge in a combustion chamber which comprises introducing to said cham ber a combustible fluid, igniting said fluid, and mingling with the hot gaseous products of combustion incombustible dust, whereby said dust is heated, and the heat distributed over the burden or charge in the combustion chamber, said dust being separate and distinct from the burden or charge.

2. The method of applying heat to a burden or charge in a combustion chamber which comprises introducing to said chamber a combustible fluid, igniting said fluid, and mingling with the hot gaseous products of combustion incombustible dust, said dust being separate and distinct from the burden or charge, causing the heat of such gaseous products to be absorbed by such dust and to be radiated therefrom to the burden or charge.

In testimony whereof we have signed our names to this specification in the. presence of two subscribing witnesses.

ANDREVV MURRAY HUNT. JAMES BUCKNER SPEED. Witnesses A. M. CoLn, D. B. RICHARDS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

